There is a rotating electrical machine known in the related art, which includes a stator winding, achieved by joining end portions of each conductor segment with one another, mounted at a stator core (see patent literature 1). Patent literature 1 discloses a stator manufacturing method for manufacturing a stator in a rotating electrical machine that includes a step in which end portions of conductor segments with an insulating film formed thereupon are plastically deformed by pressurizing the end portions with a die and a subsequent step in which the insulating film, located toward the tips of the end portions, is removed.
Once the insulating film at the end portions is removed, the conductor segments are each formed into a substantially U-shape through a bending process. The end portions of the conductor segments having been formed into the substantially U-shape are inserted through slots from one end surface of the stator core and are made to project out through another end surface of the stator core. The end portions of conductor segments adjacent to each other are pressurized and arc-welded. As a plurality of substantially U-shaped conductor segments are joined, a stator with a stator winding mounted at the stator core is manufactured.
The manufacturing method disclosed in patent literature 1, in which the end portions of the conductor segments having an insulating film formed thereupon are plastically deformed, assures reliable adhesion for the insulating film shielding the tips of each conductor segment. The manufacturing method described in patent literature 1, which allows the conductor segments to assume a small sectional area at the ends thereof, reduces the heat input during the joining process. This, in turn, keeps down the temperature in the areas near the conductor segment end portions and ultimately prevents deterioration of the insulation performance on the base side of the end portions that would otherwise occur due to degradation of the insulating film.